Bulla Regia, Tunisia – The Hidden Depths of a Roman City

Bulla Regia is one of the most remarkable archaeological sites in Tunisia, an ancient city whose greatest treasures are found not only among ruined temples, baths and streets, but beneath them.

Situated in the fertile Medjerda Valley of northwestern Tunisia, around 10 kilometres from the modern city of Jendouba, Bulla Regia occupied an important position on the route linking Carthage with Hippo Regius, modern Annaba in Algeria. The surrounding countryside was exceptionally productive, and agriculture would become the foundation of the city’s prosperity.

The origins of Bulla Regia reach back well before Roman rule. The settlement probably existed by at least the fifth century BCE and developed under strong Punic influence from Carthage. After the decline of Carthaginian power, Bulla became part of the Numidian kingdom and appears to have enjoyed royal importance. Its later name, Bulla Regia, meaning Royal Bulla, preserves the memory of this association with the Numidian monarchy.

Rome assumed direct control of the region in 46 BCE, following Julius Caesar’s victory over the forces of Pompey and the defeat of the Numidian king Juba I. Bulla was initially granted the privileged status of a free town and gradually became more deeply integrated into Roman political and cultural life. Under Vespasian in the first century CE, it gained municipal status, and during the reign of Hadrian in the second century, it became a Roman colony, formally known as Colonia Aelia Hadriana Augusta Bulla Regia.

The second and third centuries were the city’s great age of prosperity. The fertile lands surrounding Bulla produced grain, olives, and other agricultural products, while Roman Africa became one of the great food-producing regions of the empire. Wealth generated from the countryside enriched prominent local families, funded monumental public buildings, and transformed Bulla Regia into an impressive provincial city.

The prosperity of Bulla Regia was also connected to the wider resources of the region. Nearby Simitthus, modern Chemtou, was famous for its yellow marble, prized throughout the Roman Empire, and examples of this prestigious stone were used in the decoration of Bulla Regia’s public buildings.

Temples, Baths and Spectacles

At its height, Bulla Regia possessed many of the features expected of a prosperous Roman centre. Its monumental heart included a forum, a civil basilica, a curia, market and temples, while substantial bath complexes, a theatre and an amphitheatre served the public life of the city.

The Capitolium, dedicated to Jupiter, Juno, and Minerva, stood prominently beside the forum and proclaimed the city’s Roman identity. Other sanctuaries were dedicated to Apollo and Isis, revealing the mixture of religious traditions that flourished in Roman North Africa.

Among the most impressive public monuments were the Memmian Baths, constructed during the early third century CE. The complex contained a large central frigidarium, pools and heated rooms, and was associated with Iulia Memmia, daughter of a Roman consul from Bulla Regia. The scale of the baths reflects both the wealth of the city and the importance of public bathing in Roman social life.

Bulla Regia also possessed a sophisticated water system, including large cisterns that stored water for its baths, fountains, and houses.

The Roman theatre is one of the finest surviving monuments at the site. Built in the second century CE, it could accommodate several thousand spectators and was richly decorated with marble. It continued to be used into late antiquity. Around CE 399, Augustine of Hippo criticised the Christians of Bulla Regia for their enthusiasm for theatrical spectacles, providing a vivid glimpse of a city in which traditional Roman entertainments persisted alongside the growing influence of Christianity.

Yet none of these monuments has given Bulla Regia its fame.

That distinction belongs to its extraordinary private houses.

The City Beneath the City

Several of the wealthiest residents constructed villas with complete residential levels below ground. These were not crude cellars or simple shelters, but carefully planned living spaces containing courtyards, columns, corridors, bedrooms and dining rooms. Some were decorated with elaborate mosaics and architectural finishes, every bit as refined as those found above ground.

The arrangement was an ingenious response to the North African climate. During the cooler months, families could occupy the rooms at street level, where they could enjoy warmth and sunlight. In the fierce heat of summer, life could retreat underground, where the surrounding earth provided insulation and maintained more comfortable temperatures.

Light and air entered through open courtyards and carefully designed spaces. The result was a form of seasonal architecture, practical in purpose but luxurious in execution.

Several of these houses remain accessible today, allowing visitors to descend below the modern ground level and enter an unusually intimate world of Roman domestic life.

The House of Amphitrite

The most celebrated is the House of Amphitrite.

Much of its upper level has been lost, but its subterranean rooms survive in remarkable condition. A staircase descends into vaulted chambers where mosaic floors still occupy the spaces for which they were created.

Its greatest treasure is the magnificent mosaic in the underground dining room, or triclinium. For many years the central female figure was identified as Amphitrite, the sea goddess and wife of Neptune, giving the house its modern name. She is now generally recognised as Venus, or Aphrodite, rising triumphantly from the sea.

The goddess is carried by two marine centaurs, while cupids and sea creatures animate the composition. Dating to the third century CE, the mosaic remains in situ and is one of the defining images of Bulla Regia. The old name, however, has endured, and the House of Amphitrite remains one of the site’s most memorable monuments.

The residence also yielded a superb mosaic depicting Perseus rescuing Andromeda, now preserved in the Bardo Museum in Tunis. Together with the Marine Venus pavement, it reveals the taste of Bulla Regia’s wealthy residents for mythology, colour, and sophisticated artistic display.

To descend beneath the brilliant Tunisian sunlight and unexpectedly encounter Venus surrounded by the creatures of the sea is perhaps the quintessential experience of Bulla Regia.

Houses of Wealth and Luxury

Another important residence is the House of the Hunt; a large and sophisticated villa arranged across both upper and subterranean spaces. Its underground level included bedrooms and a dining room grouped around a peristyle, while surviving vaults reveal the ingenious construction methods employed by Roman builders.

The House of the Treasure received its name from a hoard of Byzantine gold coins discovered within it, evidence that wealth and occupation continued long after the city’s peak under Rome.

Other residences, including the House of the Fishing and the House of the Peacock, further demonstrate that subterranean living was a distinctive feature of elite domestic architecture at Bulla Regia rather than an isolated experiment.

The mosaics are among the great treasures of the city. Hundreds have been uncovered, and an exceptional number remain in situ. Geometric designs mingle with mythological figures, animals, hunting scenes, and marine imagery, allowing visitors to experience these works not as detached museum pieces, but within the houses and rooms for which they were originally created.

This is one of Bulla Regia’s greatest pleasures. Rather than seeing Roman domestic art isolated behind museum glass, visitors can stand within the architecture itself, surrounded by the spaces in which these mosaics once formed part of daily life.

Christianity and the Changing City

Bulla Regia did not disappear with the decline of Roman imperial power.

Christianity became established here relatively early, and a bishop is recorded in the third century. By Late Antiquity, the city possessed several churches and an important Christian community. At the Council of Carthage in CE 411, Bulla Regia was represented by rival Catholic and Donatist bishops, reflecting the religious divisions that affected North Africa during the period.

Among the surviving Christian monuments is a large basilica with a distinctive cruciform baptismal font. Other churches and cemeteries reveal that Bulla Regia remained active through the Vandal and Byzantine periods.

Its decline was gradual rather than the result of a single catastrophic earthquake. Occupation contracted over the centuries and, although parts of the city suffered structural collapse and natural damage, settlement appears to have continued well into the medieval period.

Eventually, the noble houses, streets, and public buildings disappeared beneath accumulating earth, vegetation, and collapsed masonry. Ironically, this long burial helped protect some of the very features for which Bulla Regia is now famous.

Rediscovering Bulla Regia

The ruins were known to European travellers before systematic archaeological excavation began in the late nineteenth century. Early exploration and development were not always kind to the ancient city. Railway construction through the region caused serious damage, with ancient stone reused as building material and monuments destroyed. The city’s monumental triumphal arch, still recorded during the nineteenth century, was dismantled during this period.

More systematic excavation began under French archaeologists in the late nineteenth century and expanded during the twentieth. Gradually, the earth surrendered temples, streets, mosaics and, most remarkably, the subterranean houses.

Archaeological work has continued under Tunisian and international teams, revealing that Bulla Regia has far more to tell than its Roman monuments alone. Beneath and around the visible ruins lie traces of Punic, Numidian, Roman, Christian, Vandal, Byzantine, and medieval occupation, representing more than a millennium of changing history.

Today, only part of the ancient city has been excavated.

Its theatre, temples, baths, basilicas and streets testify to centuries of public life, but its greatest fascination remains the private world beneath the earth.

Few archaeological experiences are quite like descending from the brilliant Tunisian sunlight into the cool underground rooms of Bulla Regia. Here, columns still frame ancient courtyards, vaulted chambers remain remarkably intact, and magnificent mosaics survive where Roman craftsmen laid them more than seventeen centuries ago.

Bulla Regia is not simply another ruined Roman city. It is a city of two worlds: one exposed to the North African sun, the other hidden beneath the ground.

Together they preserve an ingenious, luxurious, and remarkably intimate glimpse into life in Roman Africa.

View a selection of images from Bulla Regia.

All images, text, and content are copyright Steven Sklifas.